1. Field of the Invention
This invention relates to method and apparatus for combined electrolytic-abrasive polishing suitable for mirror finishing free curved surfaces of metallic materials.
2. Description of the Prior Art
The combined electrolytic-abrasive polishing, a technology of mirror finishing surfaces of workpiece in which a passive oxidation film formed on a work surface as a result of electrolysis is removed by abrasive grains, has heretofore been applied to flat surfaces and cylindrical or other rotational surfaces, but not to arbitrary free curved surfaces. Accordingly, the conventional polishers of this sort are not applicable to polishing of free curved surfaces.
Therefore, there have been strong demands in various technical fields for the development of techniques which facilitate mirror finishing of arbitrary free curved surfaces on molds or other metallic members with complicate surface profiles or on beads of welded stainless steel plates.
For mirror finishing of such free curved surfaces, it has been the conventional practice to resort to buffing or manual operations using a suitable abrasive tool, which not only requires meticulous skill but also involves a problem that the working environment is damaged to a considerable degree.
Further, it is extremely advantageous to perform the mirror finishing of a free curved surface automatically, following the undulations of the free curved surface. In order to achieve this by the techniques generally known in the art, it is necessary to move a tool along the profile of a free curved surface on the basis of dimensional data of the curved surface profile, which are measured beforehand or simultaneously with the polishing operation by the use of very complicated and costly automation equipment. Besides, automation of the buffing operation itself is extremely difficult.